From patchwork Wed Sep 20 20:45:19 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kees Cook X-Patchwork-Id: 9962457 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5877D60208 for ; Wed, 20 Sep 2017 20:49:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4C29B29226 for ; Wed, 20 Sep 2017 20:49:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 40E0B2922B; Wed, 20 Sep 2017 20:49:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_MED, T_DKIM_INVALID, URIBL_BLACK autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 48E8C29226 for ; Wed, 20 Sep 2017 20:49:01 +0000 (UTC) Received: (qmail 4084 invoked by uid 550); 20 Sep 2017 20:46:32 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 3701 invoked from network); 20 Sep 2017 20:46:23 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=bCuCLTk9+B6AXPP7kZ6H/admCUVFFk7+hdquAwXQrjE=; b=cobMLXMvlwTawb1WQd8DWiFLXJm10e9ZNRxneSs37XtyFkRvz1fKcheVgkhhM0wwvz rxUuMaWWzZrg7KfyDTrm4SymU0XAqDAY4Qw08zelrwLU4Z/H8rV3/8/6BtggaMU++kOM sNzEPRI2BnnBsaUb7o5I9749Iwa2YCiNjHQ8o= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=bCuCLTk9+B6AXPP7kZ6H/admCUVFFk7+hdquAwXQrjE=; b=FtRNcu9E1o3rAkOCgxPOvq85B2XGdZlvQub2HcA0L2Qox3IxN0f5F3vdYNfqSfXj4f 5IwIopnRVF2o2thCa2MJrkxaJF2YcuP2d9pT8/LivYt1gIiWLcVZ7Idu3R+NHS/ySwr0 SZWJwaB6fEHujbcY2nY2tM8JyGRBTPZJkWyaSRM6JiwZ5+YjvUlIfWY5ZG49JemC4XX/ Zj8qQKITYpdPa/ySZgWYIf8lCUmXY5IPpvN7RWsc8CA0AlKayAo3cgfZRP7Q5VVU8Kaf 2l7sY3HfSLWsiEE+Y124wyUXIfUiFItWLWjGkGlDxj1mKtnkTCDPRRgAShGLUkcTKYJj 4U5g== X-Gm-Message-State: AHPjjUgTG80mOoCA7Sr1aQlFnjpfUtig8LZ+UDlfwPRp6RSuA+nIGQ7Y TUhArBB/nDt6H64Vdgx6HURmbg== X-Google-Smtp-Source: AOwi7QC22hNjPKOL8hqCejxE5rba+Uf+JnhG2CycDnRbB80ZrYZEcSGwQnISJLLI4IHFIfD8fELKPw== X-Received: by 10.99.121.141 with SMTP id u135mr3428496pgc.262.1505940371362; Wed, 20 Sep 2017 13:46:11 -0700 (PDT) From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Kees Cook , David Windsor , Evgeniy Dushistov , linux-fsdevel@vger.kernel.org, netdev@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com Date: Wed, 20 Sep 2017 13:45:19 -0700 Message-Id: <1505940337-79069-14-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1505940337-79069-1-git-send-email-keescook@chromium.org> References: <1505940337-79069-1-git-send-email-keescook@chromium.org> Subject: [kernel-hardening] [PATCH v3 13/31] ufs: Define usercopy region in ufs_inode_cache slab cache X-Virus-Scanned: ClamAV using ClamSMTP From: David Windsor The ufs symlink pathnames, stored in struct ufs_inode_info.i_u1.i_symlink and therefore contained in the ufs_inode_cache slab cache, need to be copied to/from userspace. cache object allocation: fs/ufs/super.c: ufs_alloc_inode(...): ... ei = kmem_cache_alloc(ufs_inode_cachep, GFP_NOFS); ... return &ei->vfs_inode; fs/ufs/ufs.h: UFS_I(struct inode *inode): return container_of(inode, struct ufs_inode_info, vfs_inode); fs/ufs/namei.c: ufs_symlink(...): ... inode->i_link = (char *)UFS_I(inode)->i_u1.i_symlink; example usage trace: readlink_copy+0x43/0x70 vfs_readlink+0x62/0x110 SyS_readlinkat+0x100/0x130 fs/namei.c: readlink_copy(..., link): ... copy_to_user(..., link, len); (inlined in vfs_readlink) generic_readlink(dentry, ...): struct inode *inode = d_inode(dentry); const char *link = inode->i_link; ... readlink_copy(..., link); In support of usercopy hardening, this patch defines a region in the ufs_inode_cache slab cache in which userspace copy operations are allowed. This region is known as the slab cache's usercopy region. Slab caches can now check that each copy operation involving cache-managed memory falls entirely within the slab's usercopy region. This patch is modified from Brad Spengler/PaX Team's PAX_USERCOPY whitelisting code in the last public patch of grsecurity/PaX based on my understanding of the code. Changes or omissions from the original code are mine and don't reflect the original grsecurity/PaX code. Signed-off-by: David Windsor [kees: adjust commit log, provide usage trace] Cc: Evgeniy Dushistov Signed-off-by: Kees Cook --- fs/ufs/super.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/fs/ufs/super.c b/fs/ufs/super.c index 6440003f8ddc..62b6a4aad809 100644 --- a/fs/ufs/super.c +++ b/fs/ufs/super.c @@ -1466,11 +1466,14 @@ static void init_once(void *foo) static int __init init_inodecache(void) { - ufs_inode_cachep = kmem_cache_create("ufs_inode_cache", - sizeof(struct ufs_inode_info), - 0, (SLAB_RECLAIM_ACCOUNT| - SLAB_MEM_SPREAD|SLAB_ACCOUNT), - init_once); + ufs_inode_cachep = kmem_cache_create_usercopy("ufs_inode_cache", + sizeof(struct ufs_inode_info), 0, + (SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD| + SLAB_ACCOUNT), + offsetof(struct ufs_inode_info, i_u1.i_symlink), + sizeof_field(struct ufs_inode_info, + i_u1.i_symlink), + init_once); if (ufs_inode_cachep == NULL) return -ENOMEM; return 0;